为什么openstcak上创建很多虚拟机，会不能“nova list”？

root@ubuntu214:/usr/lib/python2.7/dist-packages/novaclient/v1_1# nova list
ERROR: The server has either erred or is incapable of performing the requested operation. (HTTP 500) (Request-ID: req-d207e219-de81-4b73-910b-acea75492c86)

产生这个原因有很多，具体看日志

更多500错误
http://so.aboutyun.com/cse/search?s=18335994984162479371&ie=gbk&q=HTTP+500&searchsubmit=true